System for injecting beneficial micro-organisms into an indoor environment

ABSTRACT

The invention pertains to a system for injecting beneficial micro-organisms into an indoor environment, the system comprising: a container (1) configured to contain a mix of micro-organisms; a nebulizer (9) arranged to spray an amount of said mix of micro-organisms into a ventilation channel of said indoor environment; a pump (4) arranged to transport said amount of said mix of micro-organisms to be nebulized from said container (1) to said nebulizer (9); a flow meter (6) arranged to measure the flow of said amount of said mix of micro-organisms; and a controller (8), operatively connected to said flow meter (6) and said pump (4), said controller (8) being configured to control at least said pump (4) in function of at least measurements of said flow meter.

FIELD OF THE INVENTION

The present invention concerns systems for improving the air quality in indoor environment, in particular by the injection of beneficial micro-organisms to improve the microbiome in indoor spaces. The present invention further pertains to a method for use in same. The present invention further pertains to a filter unit for removing particles from a gas flow and to a system for treating air to be injected into an indoor environment.

BACKGROUND

The current trend in building design is to insulate the indoor environment to a maximum extent from the outdoor environment to obtain higher energy efficiency. Air supply is implemented through forced ventilation systems, which filter the incoming air to remove pollutants. As a result, the microbiome of the atmosphere inside buildings tends to become poorer, which risks underexposing humans to micro-organisms that would be beneficial to human health.

It is known to deploy plants that are considered to have air purifying characteristics inside buildings, with a view to improving the air quality. It is a disadvantage of that approach that it is cost and labor intensive, and prone to generating undesired humidity and mold formation.

It is known to blow probiotics into the air inside a building. It is a disadvantage of that approach that it may lead to the formation of bacterial spores when certain climatological circumstances occur.

It is known to use probiotic detergents inside buildings. It is a disadvantage of that approach that the detergents tend to contain volatile organic compounds and chemicals that reduce biodiversity.

As mentioned here above, air supply is implemented through forced ventilation systems, which filter the incoming air to remove pollutants. The advantage of removing such pollutants is that the injected air becomes healthier for persons present in said indoor spaces to inhale. On the downside, known systems typically make use of HEPA filters, which have been known to remove pathogens from the air adequately, but which need a high pressure (typically at least 400 Pa) to function, making such a system energy intensive.

There therefore remains a need to provide for a system which is capable of removing a maximum of harmful organisms and pollutants from air to be injected in indoor spaces, wherein the pressure to be applied for filtering said air remains minimal.

A further downside is that the microbiome of filtered air, although cleared of pathogens, is out of balance. There further remains a need to provide for a system which can restore the microbiome balance of indoor air.

Based on the above, there therefore remains a need to provide for a system which is capable of treating air to be injected into an indoor environment, wherein such treatment consists of removing harmful pollutants and provide the air to be injected with beneficial organisms, wherein such a system is energy efficient.

SUMMARY

According to an aspect of the present invention, there is provided a system for injecting beneficial micro-organisms into an indoor environment, the system comprising:

-   -   a first container configured to contain a mix of         micro-organisms;     -   a first nebulizer arranged to spray an amount of the mix of         micro-organisms into a ventilation channel of the indoor         environment;     -   a first pump arranged to transport the amount of the mix of         micro-organisms to be nebulized from the first container to the         first nebulizer;     -   a first flow meter arranged to measure the flow of the amount of         the mix of micro-organisms; and     -   a first controller, operatively connected to the first flow         meter and the first pump, the first controller being configured         to control at least the first pump in function of at least         measurements of the first flow meter.

The present invention is based inter alia on the insight of the inventor that it is beneficial for human health to inject certain micro-organisms in the air of indoor spaces, in carefully controlled quantities. The present invention is also based on the insight of the inventor that such micro-organisms can advantageously be nebulized into a ventilation channel of an indoor environment for the purpose of distribution.

In an embodiment of the system according to the present invention, the first container is formed as a bag.

It is an advantage of the use of a bag, that the container's volume shrinks as its contents are consumed, avoiding the entry of air (and airborne particles and organisms) into the container and the ensuing risk of contamination of the remaining contents. By reducing the risk of contamination, the conservation time of the bag's contents is increased significantly. By avoiding the entry of air, and in particular of the oxygen contained in the air, the proliferation of certain undesirable organisms can be avoided as well.

In an embodiment of the system according to the present invention, the first container is attached to the circuitry of the system by means of a first releasable coupler.

It is an advantage of this embodiment that the container can be decoupled from the system in order to refill it, and subsequently reattached.

In an embodiment, the system according to the present invention further comprises a first filter.

It is an advantage of this embodiment that any impurities that may have contaminated the product during the assembly of the system (in particular during refilling or mounting of the reservoir) are removed from the mix of micro-organisms. This will keep these impurities from reaching sensitive components in the system and improve the operation and the lifespan of, in particular, the first pump and the first nebulizer.

In a particular embodiment, the first filter comprises a glass tube.

In an embodiment, the system according to the present invention further comprises a first overpressure safety.

The overpressure safety protects the first pump and any other sensitive components in the system from damage when obstructions in the circuitry would lead to an undesirable overpressure.

In an embodiment of the system according to the present invention, the first controller comprises a first network interface, the first controller being configured to provide operational parameters to an external receiver via the first network interface.

In a particular embodiment, the operational parameters comprise one or more of viscosity, temperature, volume, velocity, pressure build-up, nebulizing activity, air flow, air quality, air temperature and humidity.

It is an advantage of this embodiment that an external receiver can receive and process all data associated with the operation of the system.

In an embodiment, the system according to the present invention further comprises a first depressurizing valve.

It is an advantage of this embodiment that the built-up pressure can be released from the pump and other components in the system after each nebulizing cycle. This is advantageous from a safety point of view and increases the lifespan of the pump and any other sensitive components in the fluid distribution circuitry.

In an embodiment, the system according to the present invention further comprises a first housing enclosing at least the first pump, the first flow meter, and the first controller.

It is an advantage of this embodiment that it provides a convenient module for installation in existing buildings.

In an embodiment of the system according to the present invention, the first nebulizer comprises a first nozzle configured to inject at an angle between 30° and 60° relative to a main direction of air flow inside the ventilation channel.

In a particular embodiment, the ventilation channel comprises a substantially horizontal air duct, and the first nozzle is arranged at or near a bottom wall of the substantially horizontal air duct.

In an embodiment of the system according to the present invention, the first nebulizer comprises a plurality of first nozzles.

In an embodiment of the system according to the present invention, the mix of micro-organisms comprises Archaea.

This embodiment is based on the insight of the inventor that Archaea are suitable organisms for injection in the air of indoor spaces. Archaea are very diverse and plentiful in the Earth's soil, oceans, and fresh-water bodies, where they fulfill a key role in the planet's biogeochemical cycles. These micro-organisms get energy and nutrients from inorganic substrates such as carbon dioxide and ammonia. Hence, as chemolithotrophs they do not use organic compounds as nutrients, which renders them completely safe to humans. As these organisms operate according to the competitive exclusion principle, they physically occupy their living space whereby they suppress the presence of any other—potentially harmful—micro-organisms. This provides a way to reduce potentially harmful micro-organisms in exchange for more beneficial micro-organisms.

In an embodiment of the system according to the present invention, the mix of micro-organisms comprises Bacteria.

The mix may in particular comprise a microbial consortium comprising one or more ammonium-oxidizing strains which are generally recognized as safe (GRAS), such as Nitrosomonas, Nitrosospira, Nitrosopumilus, Cenarchaeum, Nitrosoarchaeum, Nitrosocaldus, Caldiarchaeum; and one or more GRAS strains which are commensal to the one or more ammonium-oxidizing strains, such as Acinetobacter, Alcaligenes, Arthrobacter, Azospirillum, Azotobacter, Bacillus, Beijerinckia, Enterobacter, Erwinia, Flavobacterium, Rhizobium, Serratia and Deinococcus.

Additionally or alternatively, the mix may in particular comprise judiciously selected beneficial (airborne) cyanobacteria.

In an embodiment of the system according to the present invention, the mix of micro-organisms comprises Eukaryota.

The mix may in particular comprise judiciously selected beneficial (airborne) micro-algae.

According to another aspect of the present invention, there is provided a filter unit for removing particles from a gas flow, the filter unit comprising

-   -   a second housing having an entrance and an exit for said gas         flow, wherein said second housing is part of a ventilation         channel of an indoor environment; and     -   a plurality of tubes;     -   wherein said plurality of tubes comprises at least a first         series of tubes,     -   wherein a tube of said first series is disposed in said second         housing substantially parallel with respect to other tubes of         said first series and wherein said first series is disposed         substantially perpendicularly to the gas flow through said         second housing; wherein said plurality of tubes further         comprises at least a second series of tubes,     -   wherein said second series is disposed in said second housing         downstream with respect to said first series and wherein a tube         of said second series is disposed substantially parallel with         respect to other tubes of said second and said first series;     -   wherein each tube of said plurality of tubes has a cross section         having a major axis and a minor axis, wherein said major axis is         substantially parallel with said gas flow through said second         housing.

The present invention is based inter alia on the insight that a plurality of tubes as described herein can provide for a near full retention or filtering of harmful substances at said tubes, requiring only a minimal pressure for providing air to an indoor environment. More in particular, it has been found that the disposition of tubes as described herein can filter or retain at least 80%, even at least 85%, even at least 90% and even at least 95% of airborne pathogens and/or contaminants, with respect to the total number of such contaminants and/or pathogens. Advantageously, required pressures can be lower than 30 Pa, even lower than 25 Pa, and even lower than 20 Pa. It has been found that a pressure of 15 Pa is sufficient to provide for sufficiently high flow rate.

In an embodiment of the filter unit according to the present invention, said cross section of a tube of said plurality of tubes is one of elliptical, airfoil or rounded rectangle.

It is an advantage of this embodiment that said shapes support enabling said minimal pressure, while allowing a sufficient contact surface for retaining harmful substances.

In an embodiment of the filter unit according to the present invention, the distance between the centers of a tube of said first series and a tube of said second series, measured along the gas flow, is less than the length of the major axis of said tubes.

It is an advantage of this embodiment that such a disposition support enabling said minimal required pressure.

In an embodiment of the filter unit according to the present invention, said gas is air and said particles relate to airborne particles comprising at least one of: airborne pathogens, pollen, mould spores, allergens, bacteria, dust particles, smog or soot particles.

In an embodiment of the filter unit according to the present invention, said plurality of tubes comprises at least one further series of tubes.

In an embodiment of the filter unit according to the present invention, a tube of said plurality is composed of a porous material, preferably an open cell material or an open cell foam.

In a particular embodiment, said porous material is an open cell material, wherein said cells have a cell diameter between 100 μm and 10000 μm, preferably between 500 μm and 8000 μm, and most preferably between 1000 μm and 6000 μm.

In a particular embodiment, said porous material contains one of a biopolymer, a polyurethane, a chitosane, and/or a 3D-printed material comprising at least one of a polymer and/or a metal.

In an embodiment of the filter unit according to the present invention, the filter unit further comprises at least one of

-   -   a second container for containing a virucidal, bactericidal         and/or fungicidal composition;     -   a second nebulizer for spraying an amount of said composition         into said second housing;     -   a second pump for transporting said amount of said composition         to be nebulized from said second container to said second         nebulizer;     -   a second flow meter for measuring the flow of said amount of         said composition; and     -   a second controller, operatively connected to said second flow         meter and said second pump, said second controller being         configured to control at least said second pump in function of         at least measurements of said second flow meter.

In an embodiment of the filter unit according to the present invention, said second nebulizer comprises at least one second nozzle configured to inject at an angle between 30° and 60° relative to a main direction of said gas flow inside said second housing.

In an embodiment of the filter unit according to the present invention, said ventilation channel comprising said second housing comprises a substantially horizontal air duct, and said at least one second nozzle is arranged at or near a bottom wall of said substantially horizontal air duct or second housing.

In an embodiment of the filter unit according to the present invention, said second nebulizer comprises a plurality of second nozzles.

In an embodiment of the filter unit according to the present invention, said composition comprises at least one of carrageenan, citrus extract, and/or tea extract.

According to another aspect of the present invention, there is provided a system for treating air to be injected into an indoor environment, said system comprising

-   -   one of a system for injecting micro-organisms into an indoor         environment as described herein, a method for injecting         micro-organisms into an indoor environment, and     -   a filter unit as described herein.

BRIEF DESCRIPTION OF THE FIGURES

These and other technical features and advantages of embodiments of the invention will now be described with reference to the enclosed drawings, in which:

FIG. 1 presents a schematic overview of an embodiment of the system 100 according to the present invention;

FIG. 2 is a photograph of a pump and a bypass mounted on a common bracket, as may be used in an embodiment of the system 100 according to the present invention;

FIG. 3 is a photograph of an exemplary arrangement of an OpenMotics Gateway and an OpenMotics Output Module, as may be used as a controller in an embodiment of the system according to the present invention;

FIG. 4 illustrates an exemplary arrangement of a first nebulizer in an air duct, for use in an embodiment of the system 100 according to the present invention;

FIG. 5 illustrates another exemplary arrangement of a first nebulizer in an air duct, for use in an embodiment of the system 100 according to the present invention

FIG. 6 presents a schematic overview of an embodiment of the filter unit 200 according to the present invention;

FIG. 7 illustrates an exemplary arrangement of a plurality of second nebulizers in an air duct or housing 210, for use in an embodiment of the filter unit 200 according to the present invention;

FIG. 8 illustrates a schematic overview of an embodiment of the system 500 according to the present invention.

DESCRIPTION OF EMBODIMENTS

FIG. 1 presents a schematic overview of an embodiment of the system 100 according to the present invention.

The illustrated system for injecting beneficial micro-organisms into an indoor environment comprises a first container 1 configured to contain a mix of micro-organisms.

The first container 1 may be formed as a bag. The bag may be made of recyclable materials, such as polyethylene (preferably LDPE). Other materials, such as those that are commonly used for the manufacture of IV drip bags (e.g. polyvinyl chloride), may also be used.

The first container 1 may be reusable. The container (of the ‘bag’ type or other) may be attached to the circuitry of the system 100 by means of a first releasable coupler, allowing it to be decoupled when it is empty, refilled, and reattached.

The mix of micro-organisms provided in the container may comprise Archaea. Additionally or alternatively, the mix of micro-organisms provided in the container may comprise Bacteria. Additionally or alternatively, the mix of micro-organisms provided in the container may comprise Eukaryota. The mix comprises the micro-organisms in suspension in a liquid substrate (e.g. water, an organic solution, or an inorganic solution). Upon dispersion of the mix, the micro-organisms may be sustained in droplets or become airborne.

A suitable composition of the mix of micro-organisms is disclosed in Belgian patent application publication no. BE1025316A1 in the name of Avecom NV.

The illustrated system 100 further comprises a first nebulizer 9 arranged to spray an amount of the mix of micro-organisms as an aerosol into a ventilation channel of the targeted indoor environment. The first nebulizer 9 may comprise a pressure regulator, a lance of a suitable length to bridge the distance between the location of the pressure regulator and the injection point, and a spray head at the injection point. In settings where the location of the first nebulizer 9 is prone to large temperature swings, an electronically controlled heater (such as a resistance, through which an electrical current may be sent under control of the controller 8 described below) may be provided to protect the first nebulizer 9 and neighboring components from freezing.

The illustrated system 100 further comprises a first pump 4 arranged to transport the amount of the mix of micro-organisms to be nebulized from the first container 1 to the first nebulizer 9. Any suitable electronically controllable pump for pumping liquids may be used. In an embodiment of the present invention, the first pump 4 is a membrane pump.

The illustrated system 100 further comprises a first flow meter 6 arranged to measure the flow of the amount of the mix of micro-organisms and a first controller 8, operatively connected to the first flow meter 6 and the first pump 4, the first controller 8 being configured to control at least the first pump 4 in function of at least measurements of the first flow meter.

The presence of a first flow meter 6 allows for accurate feedback-based control of the first pump 4 that feeds the first nebulizer 9. The first controller 8 may for example be configured to perform a PID control scheme, using the readings of first flow meter 6 as the feedback signal.

A suitable flow meter for use in embodiments of the system according to the present invention is the ES-FLOW™ low flow ultrasonic flow meter sold by Bronkhorst High-Tech B.V. of Ruurlo, The Netherlands. This flow meter can easily be connected to the controller by means of a serial data connection (RS232/RS485) for control and digital read-out, while also providing an alternative analog read-out option.

One or more other sensors (not illustrated) may be provided to supply other measurement values to the first controller 8. These sensors may relate to conditions of the system itself (e.g., pressure sensors to sense pressure in various parts of the system's liquid transportation circuitry, current sensors to measure the amount of electrical current by the pump) or of the environment (e.g., thermometers to measure temperature inside the building, hygrometers to measure air humidity inside the building). Other parameters that may advantageously be sensed with suitable sensors integrated in or connected to the system, because they have an impact on the general quality of the targeted indoor living environment, include: CO₂ level, concentration of volatile organic compounds, concentration of dust particles and their mass and/or size distribution, sound (noise) level, and illumination level.

The first controller 8 may be implemented in a dedicated hardware component (e.g., ASIC), a configurable hardware component (e.g., FPGA), a programmable component with appropriate software (e.g., microprocessor, DSP), or any suitable combination of such components. The same component(s) may also perform other functions. Functions to be controlled by the first controller 8 may include power up, power down, and reboot of the system, opening and closing the door of the system's enclosure, controlling valves, and controlling the first pump 4. The first pump 4 may be activated intermittently (cyclically) in accordance with the desired dosage of the mix of micro-organisms in the building's air flow. The dosage may be varied in function of the temperature and/or the humidity inside the building, if there are suitable sensors to provide these parameters to the system.

In the illustrated case, a first filter 3 is provided immediately downstream of the first container 1, to keep any impurities that may be present in the stored mix from entering the liquid transport circuitry.

In the illustrated case, a first overpressure safety 5 or bypass is provided in parallel with the first pump 4 to prevent the build-up of a potentially harmful pressure differential between the upstream side and the downstream side of the first pump 4. The first overpressure safety 5 may be mounted on a common bracket with the first pump 4 to obtain a particularly compact arrangement, as shown in FIG. 2 .

A first depressurizing valve 10 may be provided to remove pressure from the circuit when it is not in operation, e.g. after every nebulizing cycle.

In the illustrated case, a plurality of electronically controlled first valves 7 are provided to allow distribution of the mix to different circuits with respective nebulizers (not illustrated) or to a return circuit under control of the first controller 8.

Preferably, the first controller 8 comprises a network interface. The term “network interface” refers to the necessary hardware and software to allow the first controller 8 to exchange data and messages with one or more external components (in particular for the purpose of external monitoring or control). The network interface preferably operates according to one or more data networking standards, including for example standards for wired or wireless personal area networks, such as USB, IEEE Std 802.15.1 and 0.2 (“Bluetooth”), and IEEE Std. 802.15.4 (“Zigbee”); wired or wireless local area networks such as IEEE Std 802.3 (“Ethernet”) and IEEE Std 802.11 (“WiFi”); mobile networks such as GSM/EDGE/GPRS, 3G, 4G and beyond. At the transport and network layer, the network interface may use the TCP/IP protocol family. The system may further comprise advanced networking functions such as bridging, routing, authentication, and firewall, which may be provided by a separate switch or router, or integrated in the first controller 8.

The first controller 8 may be configured to receive measurement values of some or all of the aforementioned sensors via the network interface. This is particularly advantageous for sensors that are not collocated with the system.

The first controller 8 may be configured to provide operational parameters to an external receiver via the network interface. The external receiver may for example be a user interface for a human operator or a data integrator for an artificial intelligence based monitoring/controlling entity. The operational parameters may comprise one or more of viscosity, temperature, volume, velocity, pressure build-up, nebulizing activity, air flow, air quality, air temperature and humidity.

If a sufficiently advanced first controller 8 is used and the system is connected to the internet, the system according to the present invention becomes an Internet-of-Things (IoT) enabled device. The applicant has had good results using an OpenMotics Gateway with an OpenMotics Output Module as the first controller 8, whereby the Gateway provides the internet connectivity and executes the control logic, while the Output Module interfaces with the first pump 4 and other controllable components of the liquid transport circuitry. An exemplary arrangement of a OpenMotics based controller is shown in FIG. 3 . It is an advantage of the OpenMotics family of components that they can be combined in a modular way, operate on a standard 24V power supply, provide out-of-the-box network connectivity, and run on open-source firmware, hardware, and software. Detailed information about the OpenMotics family of components can be found on the OpenMotics Wiki on https://wiki.openmotics.com/index.php/The_OpenMotics_Wiki.

Some or all of components of the system may be enclosed in a first housing (not illustrated) to facilitate transport and installation in existing buildings.

The system 100 should be configured in such a way that a maximal fraction of the nebulized mix is carried along by the air moving inside the ventilation channel for distribution throughout the building, and a minimal fraction is permanently deposited on the channel's walls. Generally, a higher air velocity will lead to a better take-up of the nebulized mix. However, a judicious placement of the nebulizer also contributes to an increased take-up.

Generally, a suitable placement of the first nebulizer may be selected in function of the geometry of the ventilation channel. The skilled person may identify suitable arrangements by means of routine experiments. Some preferred arrangements are described hereinbelow, without limiting the general scope of the invention.

In a typical situation where the ventilation channel (or at least the part where the injection takes place) has a substantially constant cross section, the main direction of air flow is parallel to the walls of the ventilation channel. The first nebulizer may be arranged on a wall of the ventilation channel. In some embodiments, an attachment element of the first nebulizer may be arranged on a wall of the ventilation channel, whereby the outlet portion of the nebulizer (the nozzle mouth) can be moved relative to the attachment element and fixed at a desired point inside the ventilation channel. The attachment element may for example include articulating or sliding components for this purpose.

The first nebulizer 9 may comprise a first nozzle configured to inject the mix in the ventilation channel at an angle between 30° and 60° relative to the main direction of air flow inside said ventilation channel (which is, as the case may be, also the angle relative to the wall on which the nozzle may be arranged). Preferably, the angle is between 40° and 50°, most preferably it is approximately 45° (within 2° or less, or even exactly 45°).

Where the ventilation channel comprises a substantially horizontal air duct, the first nozzle is preferably arranged at or near a bottom wall of said substantially horizontal air duct. A non-limiting exemplary arrangement is shown in FIG. 4 , whereby a single nozzle is placed at 100 mm from the bottom wall and 100 mm from a side wall of an air direct with a substantially rectangular cross-section measuring 400 mm×250 mm (the top part of the figure represents the cross-section, the bottom part of the figure represents a side view of the relevant part of the duct). The preferred angles mentioned above may be applied, whereby this angle is the angle of the nozzle relative to said bottom wall and/or said side wall. Alternatively, the first nozzle may be directed to spray along the main direction of the air flow.

The first nebulizer 9 may comprise a plurality of nozzles. The applicant has found that good effects can be obtained with two nozzles. Another exemplary arrangement is shown in FIG. 5 , whereby a two nozzles are placed in an air duct at ⅓ of the duct height and ⅔ of the duct height, respectively, and at ¼ of the duct width from a side wall of the air duct. Without limitation, the illustrated air duct has a substantially rectangular cross-section measuring 400 mm×250 mm (the top part of the figure represents the cross-section, the bottom part of the figure represents a side view of the relevant part of the duct). The preferred angles mentioned above may be applied, whereby this angle is the angle of the nozzle relative to the nearest one of the bottom and the top wall, and/or said side wall. Alternatively, the nozzles may be directed to spray along the main direction of the air flow.

The nozzle(s) are preferably adapted to produce an extremely fine, fog-like spray. The spray exiting the nozzle is typically cone-shaped. A top angle of the spay cone is preferably between 30° and 90°, more preferably between 50° and 70°, and most preferably approximately 60°. The applicant has found that surprisingly good results could be obtained with a hollow-cone nozzle. Good results have been obtained with a hollow-cone nozzle with a 60° spray angle with a fine-mazed strainer (e.g. Lechler type 220.004), operated at a pressure of 6 bar.

FIG. 6 presents a schematic overview of an embodiment of the filter unit 200 according to the present invention.

The illustrated filter unit 200 for removing particles from a gas flow comprises a second housing 210 having an entrance 211 and an exit 212 for said gas flow.

In a typical application of the filter unit 200 as described herein, the filter unit 200 will be part of a ventilation channel for the purpose of removing harmful particles from a gas flow. The gas may refer to air, such as outside air, which has been provided by the ventilation system for being injected in an indoor environment.

Typically, the second housing 210 is integrable with or forms part of a ventilation channel of an indoor environment and may have a substantially rectangular or square cross section. Air will flow through the ventilation channel, and in its flow enter the second housing 210 through an entrance 211 and leave the second housing 210 through an exit 212.

It has been found that the filter unit 200 as described herein allows to filter or remove at least 80%, even at least 85%, even at least 90% and even at least 95% of airborne pathogens and/or contaminants, with respect to the total number of such contaminants and/or pathogens, which contaminants and/or pathogens are initially present in a gas flow or air flow moving through said filter unit 200. More in particular it has been found that said numbers of pathogens and/or contaminants can be adhered to or adsorbed to a plurality of tubes, as described herein, which tubes preferably have an open cell structure, as well as to the inner wall of the second housing 210.

It has further been found that by regularly treating said tubes in said second housing 210 with a virucidal, bactericidal and/or fungicidal composition, e.g. by spraying such a composition onto the tubes and possibly at least part of the inner wall of the second housing 210, such pathogens and/or contaminants can be effectively neutralized. Repetitively treating said tubes and inner wall increases the life of said filter unit 200. By filtering 95% of the pathogens and/or contaminants present in the incoming air, health risks for any persons present in said indoor environment and breathing in such air are greatly reduced.

It is a further advantage that the plurality of tubes as described herein can be disposed inside the second housing 210 of the filter unit 200 in such a way that only a relatively small pressure is needed to enable adequate ventilation at a sufficiently high air flow rate. It has been found that such a pressure can be lower than 30 Pa, even lower than 25 Pa, and even lower than 20 Pa. More in particular, it has been found that a pressure of 15 Pa is sufficient to provide for a ventilation channel having a sufficiently high flow rate so to provide filtered air to an indoor environment.

The filter unit 200 further comprises a plurality of tubes 220. A tube refers herein to an elongated, substantially straight, structure that is attached or is attachable at the ends to the inner wall of the second housing 210.

Said plurality of tubes 220 comprises at least a first series of tubes 221 and at least a second series of tubes 222.

A tube of said first series 221 is disposed substantially parallel or parallel with respect to other tubes of said first series 221. Two tubes are considered “substantially parallel” herein if the angle between both is 0° (parallel) to 20°. Preferably, the tubes of said first series 221 are in parallel with each other.

Said first series of tubes 221 is furthermore disposed in said second housing 210 in a substantially perpendicular or perpendicular manner with respect to the direction of the gas or air flow moving through said second housing 210. Two elements are considered “substantially perpendicular” herein if the angle between both is 90° (parallel) to 70°.

As a consequence of these two features, said first series of tubes 221 essentially forms a plane of bars, which is substantially perpendicular or perpendicular to the air flow, through which the air is forced to move. For convenience but without limiting thereto, said air flow may be considered directed along an X-axis, wherein first series of tubes 221 can be considered extending along a Y-axis.

Said second series of tubes 222 is disposed in said second housing 210 downstream with respect to said first series of tubes 221. The term “downstream” refers herein to the direction of flow of said gas flow or air flow.

A tube of said second series 222 is disposed substantially parallel or parallel with respect to other tubes of said second 222 and/or said first series of tubes 221. Preferably, the tubes of said second series 222 are in parallel with each other. Preferably, the tubes of said second series 222 are in parallel with the tubes of said first series of tubes 221.

Preferably, said second series of tubes 222 is disposed in said second housing 210 in a substantially perpendicular or perpendicular manner with respect to the direction of the gas or air flow moving through said second housing 210.

As a consequence, said second series of tubes 222 essentially forms a plane of bars along said Y-axis, which is substantially perpendicular or perpendicular to the air flow.

In embodiments according to the invention, the filter unit 200 may comprise at least one further series of tubes (not shown on the figures). A tube of said at least one further series is preferably disposed substantially parallel or parallel with respect to other tubes of said second 222 and/or said first series of tubes 221. Preferably, the tubes of said at least one further series are in parallel with each other. Preferably, said at least one further series of tubes is disposed in said second housing 210 in a substantially perpendicular or perpendicular manner with respect to the direction of the gas or air flow moving through said second housing 210.

Furthermore, each tube of said plurality of tubes 220 has a cross section which has a major axis and a minor axis, the major axis being longer that the minor axis. According to the invention, the major axis of the cross section of a tube is substantially parallel with said gas flow through said second housing 210, implying that the major axis is substantially directed along the X-axis.

Preferably, the major axis of the cross section of a tube is parallel with said gas flow through said second housing 210.

In embodiments according to the invention, said cross section of a tube has a symmetrical shape.

In embodiments according to the invention, said cross section of a tube is elliptical, an airfoil or a rounded rectangle.

Typically, said airfoil is symmetrical in shape.

In embodiments according to the invention, the distance between the centers of a tube of said first series 221 and a tube of said second series 222, measured along the gas flow (length “a” in FIG. 6 ), is less than the length of the major axis of said tubes (length “b” in FIG. 6 ). In other words, the difference in X-coordinates of the centers of a tube of said first series and a tube of said second series is smaller than the length of a major axis of said tubes. Hence, tubes of the second series of tubes 222 may be placed in between tubes of said first series 221, as shown in FIG. 6 , forcing air that has moved between two tubes of said first series of tubes 221 to flow either above or below a tube of said second series 222. In embodiments according to the invention, said first series of tubes 221 contains one tube more or one tube less than said second series of tubes 222.

In embodiments according to the invention, the gas is air, such as outside air, which has been drawn in for being injected into an indoor environment.

In embodiments according to the invention, the airborne particles relate to airborne pathogens and/or to biological contaminants, such as pollen, mould spores, fungi, allergens, bacteria, microbial pathogens, dust particles, yeast, smog and/or soot particles.

In preferred embodiments, the particles refer to bacteria and said filter unit 200 is provided for removing such particles from an air flow in number percentages as mentioned here above.

In embodiments according to the invention, each tube of said plurality of tubes 220 is made from a porous material, preferably an open cell material, such as an open cell foam. Preferably, said material is a reticulated foam.

In preferred embodiments, said open cell foam has cells having a cell diameter between 100 μm and 10000 μm, preferably between 500 μm and 8000 μm, and most preferably between 1000 μm and 6000 μm. It has been found that an open cell material or open cell foam having cells with such dimensions, wherein tubes made of such a material are disposed as described herein, allow for a combination of a minimal pressure for creating an air flow and a maximal particle removal from the gas or air flow, as described herein.

In embodiments according to the invention, said material or porous material is chosen from the following: a biopolymer, a polyurethane, a chitosane, and/or a 3D-printed material comprising at least one of a polymer and/or a metal.

In a particular embodiment, said material is a Bulpren® reticulated polyester foam.

In embodiments according to the invention, said material has a density of between 10 kg/m² and 100 kg/m³, preferably between 20 kg/m³ and 60 kg/m³. Advantageously, such low densities allow the filter unit 200 to be low weight.

In embodiments according to the invention, said material has a tensile strength of at least 40 kPa, preferably at least 50 kPa, more preferably at least 60 kPa and most preferably at least 70 kPa, measured according to ISO 1798.

In embodiments according to the invention, the filter unit 200 is further provided with at least one of the following

-   -   a second container 201 for containing a virucidal, bactericidal         and/or fungicidal composition;     -   a second nebulizer 202 for spraying an amount of said         composition into said second housing 210;     -   a second pump 203 for transporting said amount of said         composition to be nebulized from said second container 201 to         said second nebulizer 202;     -   a second flow meter 204 for measuring the flow of said amount of         said composition; and     -   a second controller 205, operatively connected to said second         flow meter 204 and said second pump 203, said second controller         205 being configured to control at least said second pump 203 in         function of at least measurements of said second flow meter 204.

The second container 201 may be formed as a bag. The bag may be made of recyclable materials, such as polyethylene (preferably LDPE). Other materials, such as those that are commonly used for the manufacture of IV drip bags (e.g. polyvinyl chloride), may also be used.

The second container 201 may be reusable. The container (of the ‘bag’ type or other) may be attached to the circuitry of the filter unit 200 by means of a second releasable coupler 206, allowing it to be decoupled when it is empty, refilled, and reattached.

The composition may contain a mixture of virucidal, bactericidal and/or fungicidal components.

Preferably, the composition comprises the components in suspension in a liquid substrate (e.g. water, an organic solution, or an inorganic solution). Upon dispersion of the composition, the components may be sustained in droplets or become airborne.

The illustrated filter unit 200 may further comprise a second nebulizer 202 arranged to spray an amount of the composition as an aerosol into the second housing 210. The second nebulizer 202 may comprise a pressure regulator, a lance of a suitable length to bridge the distance between the location of the pressure regulator and the injection point, and a spray head at the injection point. In settings where the location of the second nebulizer 202 is prone to large temperature swings, an electronically controlled heater (such as a resistance, through which an electrical current may be sent under control of the second controller 205 described below) may be provided to protect the second nebulizer 202 and neighboring components from freezing.

The illustrated filter unit 200 may further comprise a second pump 203 arranged to transport the amount of the composition to be nebulized from the second container 201 to the second nebulizer 202. Any suitable electronically controllable pump for pumping liquids may be used. In an embodiment of the present invention, the second pump 203 is a membrane pump.

The illustrated filter unit 200 may further comprise a second flow meter 204 arranged to measure the flow of the amount of the composition and a second controller 205, operatively connected to the second flow meter 204 and the second pump 203, the second controller 205 being configured to control at least the second pump 203 in function of at least measurements of the second flow meter 204.

The presence of a second flow meter 204 allows for accurate feedback-based control of the second pump 203 that feeds the second nebulizer 202. The second controller 205 may for example be configured to perform a PID control scheme, using the readings of second flow meter 204 as the feedback signal.

A suitable flow meter for use in embodiments of the system according to the present invention is the ES-FLOW™ low flow ultrasonic flow meter sold by Bronkhorst High-Tech B.V. of Ruurlo, The Netherlands. This flow meter can easily be connected to the controller by means of a serial data connection (RS232/RS485) for control and digital read-out, while also providing an alternative analog read-out option.

One or more other sensors (not illustrated) may be provided to supply other measurement values to the second controller 205. These sensors may relate to conditions of the system itself (e.g., pressure sensors to sense pressure in various parts of the system's liquid transportation circuitry, current sensors to measure the amount of electrical current by the pump) or of the environment (e.g., thermometers to measure temperature inside the building, hygrometers to measure air humidity inside the building). Other parameters that may advantageously be sensed with suitable sensors integrated in or connected to the system, because they have an impact on the general quality of the targeted indoor living environment, include: CO₂ level, concentration of volatile organic compounds, concentration of dust particles and their mass and/or size distribution, sound (noise) level, and illumination level.

The second controller 205 may be implemented in a dedicated hardware component (e.g., ASIC), a configurable hardware component (e.g., FPGA), a programmable component with appropriate software (e.g., microprocessor, DSP), or any suitable combination of such components. The same component(s) may also perform other functions.

Functions to be controlled by the second controller 205 may include power up, power down, and reboot of the system, opening and closing the door of the unit's enclosure, controlling valves, and controlling the second pump 203. The second pump 203 may be activated intermittently (cyclically) in accordance with the desired dosage of the composition for neutralizing pathogens or pollutants in the air flow. The dosage may be varied in function of the temperature and/or the humidity inside the building, if there are suitable sensors to provide these parameters to the system.

In the case illustrated in FIG. 6 , a second filter 207 is provided immediately downstream of the second container 201, to keep any impurities that may be present in the stored composition from entering the liquid transport circuitry.

In the case illustrated in FIG. 6 , a second overpressure safety 208 or bypass is provided in parallel with the second pump 203 to prevent the build-up of a potentially harmful pressure differential between the upstream side and the downstream side of the second pump 203. The second overpressure safety 208 may be mounted on a common bracket with the second pump 203 to obtain a particularly compact arrangement.

A second depressurizing valve 209 may be provided to remove pressure from the circuit when it is not in operation, e.g. after every nebulizing cycle.

In the case illustrated in FIG. 6 , a plurality of electronically controlled second valves 230 are provided to allow distribution of the composition to different circuits with respective nebulizers (not illustrated) or to a return circuit under control of the second controller 205.

Preferably, the second controller 205 comprises a network interface. The term “network interface” refers to the necessary hardware and software to allow the second controller 205 to exchange data and messages with one or more external components (in particular for the purpose of external monitoring or control). The network interface preferably operates according to one or more data networking standards, including for example standards for wired or wireless personal area networks, such as USB, IEEE Std 802.15.1 and 0.2 (“Bluetooth”), and IEEE Std. 802.15.4 (“Zigbee”); wired or wireless local area networks such as IEEE Std 802.3 (“Ethernet”) and IEEE Std 802.11 (“WiFi”); mobile networks such as GSM/EDGE/GPRS, 3G, 4G and beyond. At the transport and network layer, the network interface may use the TCP/IP protocol family. The filter unit 200 may further comprise advanced networking functions such as bridging, routing, authentication, and firewall, which may be provided by a separate switch or router, or integrated in the second controller 205.

The second controller 205 may be configured to receive measurement values of some or all of the aforementioned sensors via the network interface. This is particularly advantageous for sensors that are not collocated with the system.

The second controller 205 may be configured to provide operational parameters to an external receiver via the network interface. The external receiver may for example be a user interface for a human operator or a data integrator for an artificial intelligence based monitoring/controlling entity. The operational parameters may comprise one or more of viscosity, temperature, volume, velocity, pressure build-up, nebulizing activity, air flow, air quality, air temperature and humidity.

If a sufficiently advanced second controller 205 is used and the system is connected to the internet, the system according to the present invention becomes an Internet-of-Things (IoT) enabled device. The applicant has had good results using an OpenMotics Gateway with an OpenMotics Output Module as the second controller 205, whereby the Gateway provides the internet connectivity and executes the control logic, while the Output Module interfaces with the second pump 203 and other controllable components of the liquid transport circuitry. An exemplary arrangement of a OpenMotics based controller is shown in FIG. 3 . It is an advantage of the OpenMotics family of components that they can be combined in a modular way, operate on a standard 24V power supply, provide out-of-the-box network connectivity, and run on open-source firmware, hardware, and software. Detailed information about the OpenMotics family of components can be found on the OpenMotics Wiki on https://wiki.openmotics.com/index.php/The_OpenMotics_Wiki.

Some or all of components of the system may be enclosed in a third housing (not illustrated) to facilitate transport and installation in existing buildings.

The filter unit 200 should be configured in such a way that a maximal fraction of the nebulized composition can be received by the tubes of the plurality of tubes 220 and by the inner wall of the second housing 210. A judicious placement of the nebulizer also contributes to an increased take-up.

Generally, a suitable placement of the second nebulizer 202 may be selected in function of the geometry of the ventilation channel. The skilled person may identify suitable arrangements by means of routine experiments. Some preferred arrangements are described hereinbelow, without limiting the general scope of the invention.

In a typical situation where the ventilation channel (or at least the part where the injection takes place) has a substantially constant cross section, the main direction of air flow is parallel to the walls of the ventilation channel. The second nebulizer 202 may be arranged on a wall of the ventilation channel. In some embodiments, an attachment element of the second nebulizer 202 may be arranged on a wall of the ventilation channel, whereby the outlet portion of the second nebulizer (the nozzle mouth) can be moved relative to the attachment element and fixed at a desired point inside the ventilation channel. The attachment element may for example include articulating or sliding components for this purpose.

The second nebulizer 202 may comprise a second nozzle configured to inject the composition onto the tubes of said plurality of tubes 220 in the second housing 210 at an angle between 30° and 60° relative to the main direction of air flow inside said ventilation channel (which is, as the case may be, also the angle relative to the wall on which the nozzle may be arranged). Preferably, the angle is between 40° and 50°, most preferably it is approximately 45° (within 2° or less, or even exactly 45°).

In preferred embodiments, the second nebulizer 202 comprises a plurality of second nozzles. Preferably, said plurality of nozzles refers to 4 nozzles, which are by preference arranged in a 2×2 arrangement.

A non-limiting exemplary arrangement is shown in FIG. 7 , whereby four nozzles are placed at 100 mm from the bottom wall or 100 mm from a top wall, and 100 mm from a side wall of an air direct with a substantially rectangular cross-section measuring 400 mm×250 mm (the top part of the figure represents the cross-section, the bottom part of the figure represents a side view of the relevant part of the duct). The preferred angles mentioned above may be applied, whereby this angle is the angle of the nozzle relative to said bottom wall and/or said side wall. Alternatively, the nozzles may be directed to spray along the main direction of the air flow.

In another exemplary arrangement, not shown here, four nozzles are placed in an air duct at ⅓ of the duct height and ⅔ of the duct height, respectively, and at ¼ of the duct width from a side wall of the air duct. The preferred angles mentioned above may be applied, whereby this angle is the angle of the nozzle relative to the nearest one of the bottom and the top wall, and/or said side wall. Alternatively, the nozzles may be directed to spray along the main direction of the air flow.

The second nozzle(s) are preferably adapted to produce an extremely fine, fog-like spray. The spray exiting the nozzle is typically cone-shaped. A top angle of the spay cone is preferably between 30° and 90°, more preferably between 50° and 70°, and most preferably approximately 60°. The applicant has found that surprisingly good results could be obtained with a hollow-cone nozzle. Good results have been obtained with a hollow-cone nozzle with a 60° spray angle with a fine-mazed strainer (e.g. Lechler type 220.004), operated at a pressure of 6 bar.

FIG. 8 presents a schematic overview of an embodiment of a system 500 for treating air to be injected into an indoor environment according to the present invention.

The system 500 comprises

-   -   One of a system 100 for injecting micro-organisms into an indoor         environment as described herein, or a method for injecting         micro-organisms into an indoor environment as described herein,         and     -   a filter unit 200 as described herein.

In preferred embodiments, the system 500 comprises a system 100 for injecting micro-organisms into an indoor environment as described herein, and a filter unit 200 as described herein.

In preferred embodiments, incoming air that is to be injected in an indoor environment undergoes a two-step treatment, which consists of filtering or removing pollutants or pathogens by use of said filter unit 200 in a first step, followed by adding or injecting beneficial micro-organisms by use of said system 100 in a second step.

In preferred embodiments, components of the system 100 and the filter unit 200 may be shared or may be the same, e.g., a single controller may take up the task of said first controller 8 and said second controller 205.

While the invention has been described hereinabove with reference to specific embodiments, this was done to illustrate and not to limit the invention, the scope of which is determined by the accompanying claims. 

What is claimed is:
 1. A system for injecting beneficial micro-organisms into an indoor environment, the system comprising: a container configured to contain a mix of micro-organisms; a nebulizer arranged to spray an amount of said mix of micro-organisms into a ventilation channel of said indoor environment; a pump arranged to transport said amount of said mix of micro-organisms to be nebulized from said container to said nebulizer; a flow meter arranged to measure the flow of said amount of said mix of micro-organisms; and a controller, operatively connected to said flow meter and said pump, said controller being configured to control at least said pump in function of at least measurements of said flow meter.
 2. The system according to claim 1, wherein said container is formed as a bag, attached to circuitry of said system by means of a releasable coupler. 3.-6. (canceled)
 7. The system according to claim 1, wherein said controller comprises a network interface, said controller being configured to provide operational parameters to an external receiver via said network interface.
 8. The system according to claim 7, wherein said operational parameters comprise one or more of viscosity, temperature, volume, velocity, pressure build-up, nebulizing activity, air flow, air quality, air temperature and humidity.
 9. (canceled)
 10. The system according to claim 1, further comprising a housing enclosing at least said pump (4), said flow meter (6), and said controller (8).
 11. The system according to claim 1, wherein said nebulizer comprises a nozzle configured to inject at an angle between 30° and 60° relative to a main direction of air flow inside said ventilation channel; wherein said ventilation channel comprises a substantially horizontal air duct, and wherein said nozzle is arranged at or near a bottom wall of said substantially horizontal air duct. 12.-13. (canceled)
 14. The system according to claim 1, wherein said mix of micro-organisms comprises one or more of Archaea, Bacteria, and Eukaryota. 15.-32. (canceled)
 33. A method for injecting beneficial micro-organisms into an indoor environment, the method comprising: providing a container containing a mix of micro-organisms; having a nebulizer spray an amount of said mix of micro-organisms into a ventilation channel of said indoor environment; providing a pump to transport said amount of said mix of micro-organisms to be nebulized from said container to said nebulizer; providing a flow meter to measure the flow of said amount of said mix of micro-organisms; and providing a controller, operatively connected to said flow meter and said pump, said controller controlling at least said pump in function of at least measurements of said flow meter.
 34. The method according to claim 33, wherein said container is formed as a bag, attached to circuitry leading to said pump by means of a releasable coupler. 35.-38. (canceled)
 39. The method according to claim 33, wherein said controller comprises a network interface, said controller (8) being configured to provide operational parameters to an external receiver via said network interface.
 40. The method according to claim 39, wherein said operational parameters comprise one or more of viscosity, temperature, volume, velocity, pressure build-up, nebulizing activity, air flow, air quality, air temperature and humidity.
 41. (canceled)
 42. The method according to claim 33, further comprising a housing enclosing at least said pump, said flow meter, and said controller.
 43. The method according to claim 33, wherein said nebulizer comprises a nozzle configured to inject at an angle between 30° and 60° relative to a main direction of air flow inside said ventilation channel; wherein said ventilation channel comprises a substantially horizontal air duct, and wherein said nozzle is arranged at or near a bottom wall of said substantially horizontal air duct. 44.-45. (canceled)
 46. The method according to claim 33, wherein said mix of micro-organisms comprises one or more of Archaea, Bacteria, and Eukaryota. 47.-48. (canceled)
 49. A filter unit for removing particles from a gas flow, the filter unit comprising a second housing having an entrance and an exit for said gas flow, wherein said second housing is part of a ventilation channel of an indoor environment; and a plurality of tubes; wherein said plurality of tubes comprises at least a first series of tubes, wherein a tube of said first series is disposed in said second housing substantially parallel with respect to other tubes of said first series and wherein said first series is disposed substantially perpendicularly to the gas flow through said second housing; wherein said plurality of tubes further comprises at least a second series of tubes, wherein said second series is disposed in said second housing downstream with respect to said first series and wherein a tube of said second series is disposed substantially parallel with respect to other tubes of said second and said first series; wherein each tube of said plurality of tubes has a cross section having a major axis and a minor axis, wherein said major axis is substantially parallel with said gas flow through said second housing.
 50. The filter unit according to claim 49, wherein said cross section of a tube of said plurality of tubes is one of elliptical, airfoil or rounded rectangle.
 51. The filter unit according to claim 49, wherein the distance between the centers of a tube of said first series and a tube of said second series, measured along the gas flow, is less than the length of the major axis of said tubes.
 52. The filter unit according to claim 49, wherein said gas is air and said particles relate to airborne particles comprising at least one of: airborne pathogens, pollen, mould spores, allergens, bacteria, dust particles, smog or soot particles. 53.-56. (canceled)
 57. The filter unit according to claim 49, further comprising at least one of a second container for containing a virucidal, bactericidal and/or fungicidal composition; a second nebulizer for spraying an amount of said composition into said second housing; a second pump for transporting said amount of said composition to be nebulized from said second container to said second nebulizer; a second flow meter for measuring the flow of said amount of said composition; and a second controller, operatively connected to said second flow meter (204) and said second pump, said second controller being configured to control at least said second pump in function of at least measurements of said second flow meter.
 58. The filter unit according to claim 57, wherein said second nebulizer comprises at least one second nozzle configured to inject at an angle between 30° and 60° relative to a main direction of said gas flow inside said second housing, wherein said ventilation channel comprising said second housing comprises a substantially horizontal air duct, and wherein said at least one second nozzle is arranged at or near a bottom wall of said substantially horizontal air duct or second housing. 59.-62. (canceled) 